[1] There are different behavioral attitudes that humans accept as normal, such as grief for a loved one's suffering or death, avoiding danger, and not participating in cannibalism.
[2] The concept of normalization can be found in the work of Michel Foucault, especially Discipline and Punish, in the context of his account of disciplinary power.
Disciplinary power emerged over the course of the 19th century, came to be used extensively in military barracks, hospitals, asylums, schools, factories, offices, and so on, and hence became a crucial aspect of social structure in modern societies.
Normalization process theory has its roots in empirical studies of technological innovation in healthcare, and especially in the evaluation of complex interventions.
Normalization process theory covers four primary domains: (i) sense-making that creates coherence, (ii) organizing mental activity to manifest cognitive participation related to the behavior, (iii) operationalizing the behaviour through collective action, and (iv) appraising and adapting behaviours through reflexive monitoring.